It has been happening the past couple years going back to 2016. The game has gone to the idea of D skating the puck out of the zone(highly mobile, PMDs quarterbacking the rush), and a high offensive tempo(more wide open style), of which Q refuses to adjust to. Evidenced by his misuse of just about every Dman Bowman has brought in the past year or two. He still tries to use the stretch pass way too much. All the opposition has to do is clog the neutral zone by playing man to man in it, only one forechecker deep on the D, and the stretch pass is eliminated as an option.
They won the West last year on the backs of numerous comeback wins, elite(Vezina caliber) goaltending from Crow, and amazing backup goaltending from Darling, and luck.
As for the loss of players... Hammer was worse than Murphy this year. If you watched him play the last third of the season last year, and any this year, it's obvious he has fallen off a cliff. Panarin hurts, no arguing there, especially with Saad having a terrible(career worst) season this year. Toews was bad. Keith had a bad year also. I don't expect Saad or Keith to play that poorly next year. They'll progress back up to their mean. Toews is a question mark at this point. But we've seen a few older guys revitalize their careers this season, maybe Toews can do it too.
The systems employed by Q exposed the hell out of the D. If the D were allowed to use their best assets(their speed/ability to skate the puck out) then this year probably would have gone quite a bit different, even with Crow out.
I, and others have tried to explain all this, but you just keep screaming about how we think the "coaches forgot how to coach."